There are some bacteria in all waters. In general they carry out beneficial processes but some bacteria or other microorganisms may cause disease in humans. New water-related diseases, periodically emerge either because they are newly recognized or because their importance increases.
Links:
[1] http://admin.indiaenvironmentportal.org.in/feature-article/bacteriological-quality-water
[2] http://admin.indiaenvironmentportal.org.in/category/author/shailendra-kumar
[3] http://admin.indiaenvironmentportal.org.in/category/journal/spectrum
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-pollution
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-quality
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/health-effects
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/waterborne-diseases
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/micro-organisms